body {
  font-family: sans-serif;
  padding: 20px;
}

button {
  padding: 10px 16px;
  font-size: 16px;
  margin-bottom: 20px;
}

#result {
  margin-top: 20px;
  font-size: 18px;
}

.spinner {
  border: 6px solid #f3f3f3;
  border-top: 6px solid #3498db;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  animation: spin 1s linear infinite;
  margin-top: 20px;
}

.hidden {
  display: none;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}
